1. Field of the Invention
The present invention relates to a technique of checking whether a flash unit is connected to an imaging device such as a camera in a good state via a flash start command terminal via which a flash start command is transmitted between the imaging device and the flash unit.
2. Description of the Related Art
Japanese Patent Laid-Open No. 2000-89328 discloses a technique to check whether a flash unit is connected to an imaging device via connection terminals in a good state by performing a test communication between the imaging device and the flash unit.
In this conventional technique, the connection between the imaging device and the flash unit is checked by performing a test communication via a communication terminal disposed separately from a flash command terminal for transmitting a flash start command signal. Because the judgment is based on the test on the connection of the communication terminal, if the connection of the communication terminal is good although the connection of the flash start command (FSC) terminal is not good, this technique incorrectly determines that the connection of the FSC terminal is good. If such an incorrect judgment is made, the flash unit does not work when a picture is taken, and under-exposure occurs.